Since the advent of indoor plumbing, and particularly bathroom fixtures including water closets, a problem has existed in evacuating foul odors from the room, especially from interior rooms without windows. As building codes have been formulated, they usually require that all interior bathrooms include forced air ventilation means. This usually takes the form of forced air blowers in the ceiling to suck out undesirable odors, moisture, and the like.
It was recognized early on that it was more desirable to exhaust foul odors from adjacent the source rather than from other parts of the room.
Various toilet or water closet ventilation systems have been developed including systems for filtering the air from adjacent the toilet seat and blowing it back into the room to exhausting the same through the wall of the room and out a vent pipe. Also systems for ventilating these toilets or water closets to either the standard sewer system vent pipe or directly into the sewer have been developed.
These art systems, however, have drawbacks including 1. possible electrical hazards if liquid overflow occurs, 2. are ineffective in filtering foul odors, particularly in units that exhaust back into the room, 3. are complicated and expensive to manufacture, install and maintain, and 4. some require specially designed and manufactured water closets which effectively prevents retrofit.